tests: Make topic-filter test more predictable

Use insertion order instead of transaction hash as the id so that sorting
of entities is independent of hashes, and always returns entities in the
order in which they were created

Author: lutter

tests/integration-tests/topic-filter/schema.graphql

@@ -1,5 +1,5 @@
 type AnotherTriggerEntity @entity {
-  id: ID!
+  id: Int8!
   a: BigInt
   b: BigInt
   c: BigInt

tests/integration-tests/topic-filter/src/mapping.ts

@@ -3,7 +3,7 @@ import { AnotherTrigger } from "../generated/Contract/Contract";
 import { AnotherTriggerEntity } from "../generated/schema";
 
 export function handleAnotherTrigger(event: AnotherTrigger): void {
-  let entity = new AnotherTriggerEntity(event.transaction.hash.toHex());
+  let entity = new AnotherTriggerEntity("auto");
   entity.a = event.params.a;
   entity.b = event.params.b;
   entity.c = event.params.c;